Trunk design optimization for public switched telephone network

ABSTRACT

A method and system enable optimization of trunk group design in a public switched telephone network (PSTN). A community of interest, including two end offices connected by a direct trunk and at least one tandem switch, is identified using out-of band signaling data collected from the PSTN. An application server interfaced to the PSTN determines whether traffic in the community of interest passes through the tandem switch during a predetermined time period. When traffic passes through the tandem switch, the application server further determines whether the direct trunk between the end offices experienced an overflow condition during the same predetermined time period. When the direct trunk did not experience an overflow condition, an exchange code associated with the traffic passing through the tandem switch is designated as a misrouted code. The misrouted code is flagged so that associated traffic is redirected through the direct trunk.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to the field of telecommunications.More particularly, the present invention relates to optimizing thedesign of trunk routing among switches in a telecommunications network.

[0003] 2. Acronyms

[0004] The written description provided herein contains acronyms whichrefer to various telecommunications services, components and techniques,as well as features relating to the present invention. Although some ofthese acronyms are known, use of these acronyms is not strictlystandardized in the art. For purposes of the written description herein,the acronyms are defined as follows:

[0005] Answer Complete Message (ACM)

[0006] Answer Message (ANM)

[0007] Call Detail Record (CDR)

[0008] Centum-Call Seconds (CCS)

[0009] Central Exchange Service (Centrex)

[0010] Carrier Identification Code (CIC)

[0011] Competitive Local Exchange Carrier (CLEC)

[0012] Data Collection Operations System (DCOS)

[0013] Electronic Key Telephone System (EKTS)

[0014] Generic Access Profile (GAP)

[0015] Grade of Service (GOS)

[0016] Graphical User Interface (GUI)

[0017] HyperText Mark-Up Language (HTML)

[0018] HyperText Transfer Language Protocol (HTTP)

[0019] Incumbent Local Exchange Carrier (ILEC)

[0020] Initial Address Message (IAM)

[0021] Interexchange Carrier (IXC)

[0022] Internet Service Provider (ISP)

[0023] Local Exchange (NXX)

[0024] Local Routing Number (LRN)

[0025] Numbering Plan Area (NPA)

[0026] Plain Old Telephone Service (POTS)

[0027] Private Branch Exchange (PBX)

[0028] Public Switched Telephone Network (PSTN)

[0029] Release (REL)

[0030] Release Complete (RLC)

[0031] Secure Sockets Layer (SSL)

[0032] Service Control Point (SCP)

[0033] Service Switching Point (SSP)

[0034] Signaling System 7 (SS7)

[0035] Signaling Transfer Point (STP)

[0036] Transaction Capabilities Application Part (TCAP)

[0037] Transmission Control Protocol/Internet Protocol (TCP/IP)

[0038] Trunk Circuit Identification Code (TCIC)

[0039] Trunk Integrated Records Keeping System (TIRKS)

[0040] Total Network Data System (TNDS)

[0041] 3. Background Information

[0042] The public switched telephone network (PSTN) consists generallyof a series of switches capable of logically routing calls through thetelecommunications network based, in part, on call origin anddestination. Commonly, the PSTN includes two types of switches: classfive switches, also known as an end office or a service switching point(SSP), and class four switches, also known as a tandem switch. Theswitches are controlled by associated signaling transfer points (STPs)and service control points (SCPs), which provide instruction on callrouting, as well as a variety of network implemented call services.

[0043] The end offices connect the PSTN to the network users' telephonesystems, including business related Centrex and private branch exchange(PBX) systems, as well as the plain old telephone service (POTS)systems, relied on by most residential customers. Other users involveentire networks, such as Internet service providers (ISP) and the like.The tandem switches are intermediate switches, incorporated in routingbetween the originating end office and the terminating end office. Thevarious switches in the PSTN are connected by communication lines calledtrunks. A group of similar trunks that connect the same geographiclocations are referred to as trunk groups. Depending on the volume oftraffic, several trunk groups may simultaneously service two particularpoints in the PSTN.

[0044] The trunk groups interconnecting the switches are designed andimplemented based on analysis of telecommunications traffic, which hasconsistently and dramatically increased over the past several years.Trunk planners and network design engineers attempt to identifycommunications paths among switches that carry an especially high amountof traffic or load from point to point. Switches carrying especiallyhigh loads are connected with direct trunk groups to accommodate thetraffic, preferably without wasting resources. As PSTN trafficincreases, along with the number of interconnecting carriers, such ascompetitive local exchange carriers (CLECs), wireless carriers,interexchange carriers (IXCs) and independent carriers, the new andshifting traffic depend largely on tandem switches as primary hubs. Theincreased traffic loads and carriers have exhausted the tandem switchesdriving increased capital investment in the PSTN (e.g., additionaltandem switches and associated trunk groups). Often, though, tandemswitches and trunk groups are added to relieve overburdened resources,while other existing tandem switches and trunk groups are not being usedto their fullest capacity. This misuse of resources is due to thelimited ability to accurately quantify and analyze the actual trafficloads at each tandem switch.

[0045] The dynamic nature of network traffic enables continualproduction of new and different “communities of interest” between endoffices, which create opportunities to off-load traffic from theexhausted tandem switches. There are various types of communities ofinterest, the respective identities of which depend on purpose andlocation. For example, ISP traffic is a community of interest based on acentralized ISP location, which ordinarily exists outside a majormetropolitan area. In contrast, a business related community ofinterest, involving a Centrex system, for example, would likely becentered in a metropolitan area, requiring an entirely different routingscheme.

[0046] Under the existing methodology, however, opportunities tooff-load traffic are difficult, if not impossible, to identify. Forexample, in the past, network designers have analyzed traffic loads on aswitch by switch basis, looking at the inbound and the outbound loads atan end office, only, and primarily relying on manual quantification ofthe required trunk groups between any two end points. The quantificationdata was largely anecdotal (e.g., statistical and empirical sampling),as opposed to empirically comprehensive. The designers were not able toprecisely correlate a set of intervening tandem switches that enabledthe line of communication for two end points (e.g., a point to pointcommunity of interest). Also, the designers were not able to effectivelyimplement information that was potentially available to them. Therefore,it was difficult to identify and size new high usage groups within thePSTN, leaving the bulk of the communications traffic on the tandemswitches.

[0047] The present invention overcomes the problems associated with theprior art, as described below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The present invention is further described in the detaileddescription that follows, by reference to the noted drawings by way ofnon-limiting examples of embodiments of the present invention, in whichlike reference numerals represent similar parts throughout several viewsof the drawings, and in which:

[0049]FIG. 1 is a block diagram showing an exemplary telecommunicationsnetwork for trunk design optimization, according to an aspect of thepresent invention;

[0050]FIG. 2 is a flowchart of exemplary application logic foridentifying new high usage direct trunk groups, according to an aspectof the present invention;

[0051]FIG. 3 is a block diagram showing an exemplary telecommunicationsnetwork for trunk design optimization indicating new direct trunk grouprouting, according to an aspect of the present invention;

[0052]FIG. 4 is a flowchart of exemplary application logic foridentifying new intermediate high usage direct trunk groups, accordingto an aspect of the present invention;

[0053]FIG. 5 is a block diagram showing an exemplary telecommunicationsnetwork for trunk design optimization indicating potential trunk grouprouting to a new tandem switch, according to an aspect of the presentinvention; and

[0054]FIG. 6 a flowchart of exemplary application logic for identifyingtraffic misroutes, according to an aspect of the present invention

DETAILED DESCRIPTION OF EMBODIMENTS

[0055] The present invention relates to trunk design optimization thatis based on collection of empirical routing data collected using, forexample, signaling system 7 (SS7) out-of-band signaling data. Theexisting telephone call routing is monitored among end office and tandemswitches in the PSTN. The monitoring enables network designers toidentify potential direct routing opportunities, which may be ultimatelyimplemented depending on other design parameters. Also, the presentinvention enables accurate and timely identification of misroutedtraffic, which may be redirected by design to further increase telephonetraffic routing efficiency of the PSTN.

[0056] The monitoring specifically enables peak busy hour offered loadto be determined between sets of switches, including two end offices,two tandem switches or an end office and a tandem switch, which arereferred to as point-to-point communities of interest. The peak busyhour offered load includes the minutes of use generated as a result ofcalls originating on either end of a trunk. Offered load differs fromcarried load, for example, in that carried load represents the trafficactually carried over a particular trunk, while offered load includestraffic offered to the trunk, but ultimately routed elsewhere orotherwise blocked. The aggregate peak busy hour offered load representsthe maximum minutes of use offered to the network.

[0057] The primary objective is to optimally design the PSTN trunknetwork by routing traffic more efficiently over the existing trunk andswitching infrastructure, including relieving loads on over-burdenedtandem switches, as well as identifying and addressing overflowconditions and traffic misroutes. The most cost effective routes aredetermined based on continually revised data collected from within thePSTN, while maintaining the objective grade of service for thecustomers. Significant cost savings are realized by relieving congestedtandem switches and increasing the loading on under-utilized tandemswitches. Also, capital investment in the PSTN is reduced by minimizingthe need for additional physical equipment (i.e., new tandem switches).

[0058] In view of the above, the present invention through one or moreof its various aspects and/or embodiments is presented to accomplish oneor more objectives and advantages, such as those noted below.

[0059] An aspect of the present invention provides a method foridentifying misrouting of traffic in a telecommunications network. Themethod includes identifying a community of interest based on callsignaling data, the community of interest including at least oneintermediate switching location connected to a first terminal switchinglocation connected by a direct trunk to a second terminal switchinglocation. The call signaling data may include out-of-band signalingdata, such as SS7 messages, collected from the intermediate switchinglocation. The intermediate and terminal switching locations may be classfour and class five switches, respectively.

[0060] It is determined whether traffic in the community of interestpasses through the intermediate switching location during apredetermined time period and whether the direct trunk experienced anoverflow condition during the same predetermined time period. Whentraffic in the community of interest is determined to have passedthrough the intermediate switching location during the predeterminedtime period, and the direct trunk is determined not to have experiencedan overflow condition during the predetermined time period, anidentifier associated with the traffic that passed through theintermediate switching location is designated as misrouted traffic. Theidentifier may be an exchange code, such as a numbering plan area(NPA)/local exchange (NXX) code.

[0061] The method may further include flagging the identifier associatedwith the misrouted traffic to redirect the misrouted traffic through thedirect trunk. Also, a volume of the misrouted traffic may be identifiedand a load on the intermediate switch attributed to the misroutedtraffic based on the volume may be quantified.

[0062] Another aspect of the present invention provides a method foridentifying misrouting of traffic in a community of interest of atelecommunications network, the community of interest including at leasta tandem switch connected to a first end office switch connected by adirect trunk to a second end office switch. The method includesgenerating a base component relating to the community of interest basedon out-of-band signaling data, which may include SS7 messages. The basecomponent includes predetermined time periods and a volume of trafficpassing through the tandem switch during each of the predetermined timeperiods.

[0063] The method determines whether the base component indicatestraffic through the tandem switch in the community of interest during atleast one of the predetermined time periods. When the tandem switchshows traffic, the method determines whether the direct trunkexperienced an overflow condition during the corresponding predeterminedtime period. When the direct trunk did not experience an overflowcondition, at least one unique code associated with the community ofinterest is identified as a misrouted code. The unique code may includean NPA/ NXX code. The method may further include identifying a volume ofthe traffic associated with the misrouted code and quantifying a load onthe tandem switch attributed to the misrouted traffic.

[0064] Another aspect of the present invention provides a system foridentifying misrouting of traffic in a telecommunications network, thesystem including a data collection application device, configured toreceive out-of-band signaling data from the PSTN, and an applicationserver connected to the data collection application device. Theout-of-band signaling data may include SS7 messages, for example. Theapplication server identifies a community of interest in the PSTN basedon the out-of-band signaling data received by the data collectionapplication device. The community of interest includes at least oneintermediate switching location connected to a first terminal switchinglocation and a second terminal switching location, where the firstterminal switching location is connected by a direct trunk to the secondterminal switching location.

[0065] The application server determines whether traffic in thecommunity of interest passes through the intermediate switching locationduring a predetermined time period and whether the direct trunkexperienced an overflow condition during the predetermined time period.When traffic in the community of interest is determined to have passedthrough the intermediate switching location and the direct trunk isdetermined not to have experienced an overflow condition during thepredetermined time period, the application server designates anidentifier associated with the traffic as misrouted traffic. Theidentifier may include an NPA/NXX code.

[0066] The system may further include an application database, connectedto the application server. The application database stores informationrelating to at least the community of interest, the determination ofwhether the traffic passed through the intermediate switching locationduring the predetermined time period, the determination of whether thedirect trunk group experienced an overflow condition during thepredetermined time period, and the identifier. Also, the system mayinclude a data network connecting the application server and theapplication database to at least one graphical user interface andenabling analysis of the stored information.

[0067] Another aspect of the present invention provides a system foridentifying misrouting of traffic in a community of interest of a PSTN,the community of interest including at least one tandem switch connectedto a first end office switch connected by a direct trunk to a second endoffice switch. The system includes an SS7 data collection device,configured to receive out-of-band signaling data from the PSTN, and anapplication server connected to the data collection device.

[0068] The application server identifies the community of interest anddetermines whether traffic in the community of interest passes throughthe tandem switch during a predetermined time period, based on theout-of-band signaling data provided by the data collection device. Whentraffic is determined to have passed through the tandem switch, theapplication server further determines whether the direct trunkexperienced an overflow condition during the predetermined time period.When the direct trunk did not experience an overflow condition, theapplication server designates at least one exchange code associated withthe traffic that passed through the tandem switch as a misrouted code.The application server, together with an associated database, isconfigured to provide information relating to at least the community ofinterest, the tandem switch and the misrouted code to at least onegraphical user interface. The application server may further identify avolume of the traffic having the misrouted code and quantify a load onthe tandem switch attributed to the misrouted traffic based on thevolume.

[0069] Yet another aspect of the present invention provides a computerreadable medium for storing a computer program that identifiesmisrouting of traffic in a community of interest of a telecommunicationsnetwork, where the community of interest includes at least a tandemswitch connected to a first end office switch and a second end officeswitch. The computer readable medium includes a generating source codesegment that generates a base component relating to the community ofinterest based on out-of-band signaling data, the base componentincluding multiple predetermined time periods and a volume of trafficpassing through the tandem switch in the community of interest duringeach of the plurality of predetermined time periods. The out-of-bandsignaling data may include SS7 messages. The computer readable mediumfurther includes a determining source code segment that determineswhether the base component indicates traffic through the tandem switchduring at least one of the predetermined time periods and, when thetandem switch shows traffic, determines whether the direct trunkexperienced an overflow condition during the corresponding predeterminedtime periods. The computer readable medium also includes an identifyingsource code segment that identifies at least one unique code associatedwith the community of interest as a misrouted code when the direct trunkdid not experience an overflow condition during the correspondingpredetermined time period. The computer readable medium may furtherinclude a quantifying source code segment that identifies a volume ofthe traffic associated with the misrouted code and quantifies a load onthe tandem switch attributed to the misrouted traffic.

[0070] Another aspect of the present invention provides a method fordesigning a telecommunications network to improve call traffic routingefficiency with respect to at least one community of interest in thetelecommunications network, the community of interest including at leasta first end office switch and a second end office switch. The methodincludes collecting out-of-band signaling data from thetelecommunications network, quantifying a peak busy hour offered loadfor the community of interest based on the out-of-band signaling data,and determining whether the peak busy hour offered load for thecommunity of interest exceeds a predetermined threshold. When the peakbusy hour offered load exceeds the predetermined threshold, it isdetermined whether the first end office switch and second end officeswitch are connected by a direct trunk. When the first and second endoffice switches are not connected by a direct trunk, the community ofinterest is identified as a primary high usage direct trunk opportunityand data relating to the identified direct trunk opportunity is storedin an application database. The stored data includes at least anidentification of the first and second end office switches and sizinginformation relating to the direct trunk opportunity. When the first andsecond end office switches are connected by a direct trunk, the directtrunk may be identified as an augment opportunity for at least one otherdirect trunk existing in the telecommunications network. The augmentopportunity data is then stored, including at least an identification ofthe first and second end office switches.

[0071] Another aspect of the present invention provides a method fordesigning a telecommunications network to improve call traffic routingefficiency with respect to at least one community of interest in thetelecommunications network, the community of interest including at leastan end office switch and a tandem switch. The method includes collectingout-of-band signaling data from the telecommunications network,quantifying a peak busy hour offered load for the community of interestbased on the out-of-band signaling data, and determining whether thepeak busy hour offered load for the community of interest exceeds apredetermined threshold. When the peak busy hour offered load exceedsthe predetermined threshold, it is determined whether the end officeswitch and tandem switch are connected by a direct trunk. When theswitches are not connected by a direct trunk, the community of interestis identified as an intermediate high usage direct trunk opportunity anddata relating to the identified direct trunk opportunity is stored in anapplication database. The stored data includes at least anidentification of the end office switch and the tandem switch, andsizing information relating to the direct trunk opportunity. When theswitches are connected by a direct trunk, the direct trunk may beidentified as an augment opportunity for at least one other direct trunkexisting in the telecommunications network. The augment opportunity datais then stored, including at least an identification of the end officeswitch and the tandem switch.

[0072] Another aspect of the present invention provides a method fordesigning a telecommunications network to improve call traffic routingefficiency with respect to at least one community of interest in thetelecommunications network, the community of interest including at leasttwo switches, corresponding to endpoints of the community of interest.The method includes collecting signaling data from thetelecommunications network, quantifying a peak busy hour offered loadfor the community of interest based on the signaling data, anddetermining whether the peak busy hour offered load for the community ofinterest exceeds a predetermined threshold. When the peak busy houroffered load exceeds the predetermined threshold, it is determinedwhether the two switches are connected by a direct trunk. When twoswitches are not connected by a direct trunk, the community of interestis identified as a direct trunk opportunity and the direct trunkopportunity is sized based on the peak busy hour offered load for thecommunity of interest. Data relating to the identified direct trunkopportunity is stored in an application database, the data including atleast an identification of the two switches and the sizing information.When the two switches are determined to be connected by a direct trunk,the direct trunk is identified as an augment opportunity for at leastone other community of interest in the telecommunications network andaugment opportunity data relating to the augment opportunity is storedin the application database, the augment opportunity data including atleast an identification of the two switches.

[0073] The methods for designing a telecommunications network to improvecall traffic routing efficiency, described above, may further includeaccessing the application database from a graphical user interface. Thestored data is retrieved from the application database and displayed atthe graphical user interface. An improvement is then designed to thecall traffic routing efficiency in the telecommunications network basedat least the displayed stored data. The application database may beaccessed by connecting to an application server through a packetswitched data network from the graphical user interface, the applicationserver being in communication with the application database.

[0074] Another aspect of the present invention provides a system fordesigning a telecommunications network to improve call traffic routingefficiency with respect to at least one community of interest in thePSTN, the community of interest including at least a first end officeswitch and a second end office switch. The system includes a signalingdata collection device, configured to receive signaling data from thePSTN, an application server connected to the data collection device, andan application database, connected to the application server. Theapplication server identifies the community of interest, quantifies apeak busy hour offered load corresponding to the community of interestbased on the signaling data, and determines whether the peak busy houroffered load exceeds a predetermined threshold.

[0075] When the peak busy hour offered load exceeds the predeterminedthreshold, the application server further determines whether a directtrunk connects the first and second end office switches in the communityof interest. When the first and second end offices are not connected bya direct trunk, the application server identifies a primary high usagedirect trunk opportunity between the first and second end officeswitches and the application database stores information related to thehigh usage direct trunk opportunity, including identification of thefirst and second end office switches and sizing information related tothe primary high usage direct trunk group opportunity. When the firstand second end offices are connected by a direct trunk, the applicationserver identifies the direct trunk as an augment opportunity for atleast one other community of interest in the PSTN, and the applicationdatabase stores information related to the augment opportunity. Theinformation includes identification of the first and second end officeswitches and the direct trunk.

[0076] Another aspect of the present invention provides a system fordesigning a telecommunications network to improve call traffic routingefficiency with respect to at least one community of interest in thePSTN, the community of interest including at least an end office switchand a tandem switch. The system includes a signaling data collectiondevice, configured to receive signaling data from the PSTN, anapplication server connected to the data collection device, and anapplication database, connected to the application server. Theapplication server identifies the community of interest, quantifies apeak busy hour offered load corresponding to the community of interestbased on the signaling data, and determines whether the peak busy houroffered load exceeds a predetermined threshold.

[0077] When the peak busy hour offered load exceeds the predeterminedthreshold, the application server further determines whether a directtrunk connects the end office switch and the tandem switch. When theswitches are not connected by a direct trunk, the application serveridentifies an intermediate high usage direct trunk opportunity betweenthe switches and the application database stores information related tothe intermediate high usage direct trunk opportunity, includingidentification of the end office switch and the tandem switch, andsizing information related to the intermediate high usage direct trunkgroup opportunity. When the switches are connected by a direct trunk,the application server identifies the direct trunk as an intermediateaugment opportunity for at least one other community of interest in thePSTN, and the application database stores information related to theintermediate augment opportunity. The information includesidentification of the end office switch, the tandem switch and thedirect trunk.

[0078] The systems for designing a telecommunications network to improvecall traffic routing efficiency, described above, may further include apacket switched data network connecting the application server to atleast one graphical user interface. The application server may thenretrieve the stored information from the application database anddisplay the stored information at the graphical user interface, enablingdesign of improved call traffic routing efficiency.

[0079] Yet another aspect of the present invention provides a computerreadable medium storing a computer program that enhances designing of atelecommunications network to improve call traffic routing efficiencywith respect to at least one community of interest in thetelecommunications network. The community of interest includes at leasttwo switches corresponding to endpoints of the community of interest.The computer readable medium includes a data collection source codesegment that collects out-of-band signaling data from thetelecommunications network; a quantifying source code segment thatquantifies a peak busy hour offered load for the community of interestbased on the out-of-band signaling data; and a determining source codesegment that determines whether the peak busy hour offered load for thecommunity of interest exceeds a predetermined threshold and, for eachpeak busy hour offered load exceeding the predetermined threshold, thatdetermines whether the two switches of the community of interest areconnected by a direct trunk. The computer readable medium furtherincludes an identifying source code segment that identifies a directtrunk opportunity for when the two endpoint switches are determined notto be connected by a direct trunk and a sizing source code segment thatestimates a size of the direct trunk opportunity based on the peak busyhour offered load. There is also a storing source code segment thatstores data relating to the direct trunk opportunity in an applicationdatabase, the data comprising at least an identification of the twoendpoint switches and the sizing information.

[0080] In addition, the computer readable medium may include anaugmentation source code segment that identifies the direct trunk as anaugment opportunity for at least one other community of interest in thetelecommunications network when the two switches are determined to beconnected by the direct trunk. The storing source code segment may thenstore data relating to the augment opportunity in the applicationdatabase. The augment data includes at least an identification of thetwo endpoint switches and the direct trunk.

[0081] Another aspect of the present invention provides a method forincreasing call traffic routing efficiency in a telecommunicationsnetwork to improve call traffic routing efficiency with respect tointermediate high usage direct trunk opportunities in atelecommunications network. The method includes identifying at least afirst terminal switching location in the telecommunications network thathas been rehomed to a first intermediate switching location and at leasta second terminal switching location in the telecommunications networkthat is homed to an intermediate switching location other than the firstintermediate switching location. A first peak load is quantified, basedon signaling data collected from the telecommunications network, betweenthe first terminal switching location and the second terminal switchinglocation. It is determined whether the first peak load exceeds apredetermined amount.

[0082] When the first peak load exceeds the predetermined amount, aroute between the second terminal switching location and the firstintermediate switching location is identified as a new intermediate highusage direct trunk opportunity. The new intermediate high usage directtrunk opportunity is sized based on the signaling data and data relatingto the new intermediate high usage direct trunk opportunity is stored inan application database. The data includes at least identification ofthe first and second terminal switching locations, the firstintermediate switching location and the sizing information.

[0083] The method may further include identifying at least a thirdterminal switching location in the telecommunications network that isoriginally homed to the first intermediate switching location. A secondpeak load is then quantified based on the signaling data collected fromthe telecommunications network between the third terminal switchinglocation and the second terminal switching location. It is determinedwhether the second peak load exceeds the predetermined amount. When thesecond peak load exceeds the predetermined amount, a route between thesecond terminal switching location and the third terminal switchinglocation is identified as a second new intermediate high usage directtrunk opportunity and the second new intermediate high usage directtrunk opportunity is sized based on the signaling data. The datarelating to the second new intermediate high usage direct trunkopportunity is stored in the application database. The data includes atleast identification of the second and third terminal switchinglocations, the first intermediate switching location and the sizinginformation related to the second new intermediate high usage directtrunk opportunity.

[0084] Another aspect of the present invention provides a method fordesigning a telecommunications network to improve call traffic routingefficiency, the telecommunications network including multiple end officeswitches and tandem switches, where at least a first end office switchof the multiple end office switches is rehomed to a new tandem switch ofthe multiple tandem switches. The method includes collecting out-of-bandsignaling data from the telecommunications network and identifying atleast one homed end office switch of the multiple end office switches,including the first end office switch, that is homed to the new tandemswitch. At least one far end office switch of the multiple end officeswitches is identified, where the far end office switch is homed to atandem switch other than the new tandem switch.

[0085] A peak busy hour offered load is quantified between each homedend office switch and each far end office switch, based on theout-of-band signaling data. It is determined whether each peak busy houroffered load exceeds a predetermined amount. For each peak busy houroffered load that exceeds the predetermined amount, a route isidentified between the corresponding far end office switch and the newtandem switch as a new intermediate high usage direct trunk opportunity.Each new intermediate high usage direct trunk opportunity is sized basedon the out-of-band signaling data. Data relating to each identified newintermediate high usage direct trunk opportunity is stored in anapplication database, the data including at least information relatingto the corresponding far end office switch, the new tandem switch andthe sizing.

[0086] The methods for increasing call traffic routing efficiency in atelecommunications network to improve call traffic routing efficiencywith respect to intermediate high usage direct trunk opportunities,described above, may further include accessing the application databaseto retrieve the stored data and designing an improvement to thetelecommunications network to increase call traffic routing efficiencybased on at least the stored data. Accessing the application databaseincludes connecting to an application server through a packet switcheddata network from a graphical user interface, the application serverbeing in communication with the application database. The stored data isretrieved from the application database and displayed the stored data atthe graphical user interface.

[0087] Another aspect of the present invention provides a system forincreasing call traffic routing efficiency in a telecommunicationsnetwork, including a data collection application device, configured toreceive signaling data from the PSTN, and an application serverconnected to the data collection application device. The applicationserver identifies at least a first terminal switching location in thetelecommunications network that has been rehomed to a first intermediateswitching location in the telecommunications network; identifies atleast a second terminal switching location that is homed to anintermediate switching location other than the first intermediateswitching location; quantifies a first peak load between the secondterminal switching location and the first intermediate switchinglocation based on the signaling data; and determines whether the firstpeak load exceeds a predetermined amount. When the first peak loadexceeds the predetermined amount, the application server identifies aroute between the second terminal switching location and the firstintermediate switching location as a new intermediate high usage directtrunk opportunity and estimates a size of new intermediate high usagedirect trunk opportunity based on the signaling data.

[0088] The system for increasing call traffic routing efficiency in atelecommunications network may further include an application database,connected to the application server. The application database storesinformation relating to the new intermediate high usage direct trunkopportunity, the data including at least identification of the first andsecond terminal switching locations, the first intermediate switchinglocation and the sizing information related to the new intermediate highusage direct trunk opportunity. The application server may also beconnected to at least one graphical user interface, enabling analysis ofthe stored information.

[0089] Another aspect of the present invention provides a system fordesigning a telecommunications network to improve call traffic routingefficiency with respect to a multiple end office switches and tandemswitches in the PSTN, where at least one of the end office switches isrehomed to a new tandem switch. The system includes an out-of-bandsignaling data collection device, configured to receive signaling datafrom the tandem switches in the PSTN, an application server connected tothe data collection device, and an application database, connected tothe application server. The application server identifies at least onehomed end office switch of the multiple end office switches that ishomed to the new tandem switch, including the at least one end officeswitch, and identifies at least one far end office switch of themultiple end office switches that is homed to a tandem switch other thanthe new tandem switch. The application server also quantifies a peakbusy hour offered load between each homed end office switch and each farend office switch, based on at least the signaling data, and determineswhether each peak busy hour offered load exceeds a predetermined amount.

[0090] For each peak busy hour offered load that exceeds thepredetermined amount, the application server identifies a route from thecorresponding far end office switch and the new tandem switch as a newintermediate high usage direct trunk opportunity and sizes the newintermediate high usage direct trunk opportunity. Also, the applicationdatabase stores data relating to each identified new intermediate highusage direct trunk opportunity. The data includes at least informationrelating to the corresponding far end office switch, the new tandemswitch and the sizing information related to the new intermediate highusage direct trunk opportunity.

[0091] Yet another aspect of the present invention provides a computerreadable medium storing a computer program that enhances designing of atelecommunications network to improve call traffic routing efficiency,the telecommunications network including multiple end office switchesand tandem switches, such that at least a first end office switch of themultiple end office switches is rehomed to a new tandem switch of themultiple tandem switches. The computer readable medium includes a datacollecting source code segment, an identifying source code segment, aquantifying source code segment, a determining source code segment, asizing source code segment and a storing source code segment. The datacollecting source code segment collects out-of-band signaling data fromthe telecommunications network. The identifying source code segmentidentifies at least one homed end office switch of the multiple endoffice switches that is homed to the new tandem switch, including thefirst end office switch, and identifies at least one far end officeswitch of the multiple end office switches that is homed to a tandemswitch other than the new tandem switch. The quantifying source codesegment quantifies a peak busy hour offered load between each homed endoffice switch and each far end office switch, based on the out-of-bandsignaling data. The determining source code segment determines whethereach peak busy hour offered load exceeds a predetermined amount and, foreach peak busy hour offered load that exceeds the predetermined amount,identifies a route between the corresponding far end office switch andthe new tandem switch as a new intermediate high usage direct trunkopportunity. The sizing source code segment then calculates an estimatedsize of the new intermediate high usage direct trunk opportunity basedon the out-of-band signaling data and the storing source code segmentstores data relating to each identified new intermediate high usagedirect trunk opportunity in an application database. The stored dataincludes at least information relating to the corresponding far endoffice switch, the new tandem switch and the new intermediate high usagedirect trunk opportunity sizing.

[0092] The various aspects and embodiments of the present invention aredescribed in detail below.

[0093] The present invention enables analysis of call traffic withinpoint-to-point communities of interest based on empirical data collectedfrom the PSTN and based on actual out-of-band signaling data. Becausethe data collection and analysis process is ongoing, the PSTN routingmay be continually monitored and redesigned to meet constantly evolvingnetwork conditions. The constantly evolving network conditions includetraffic trends and interconnection dynamics that accommodate the largeand ever increasing variety of telecommunications providers, such asCLECs, IXCs, ILECs and wireless providers. Also, actual PSTN usagechanges based on the time of day, as well as the season of the year.Other exemplary design considerations include transit traffic, Internetdial-up traffic hold times, ISP migrations and regulatory mandates(e.g., local number portability, number pooling, etc.).

[0094] Because of the variety of the considerations affecting PSTNrouting, the present invention focuses on the peak busy hour offeredload for each tandem switch, servicing multiple end offices. In anembodiment, the peak busy hour offered load for individual end officesmay also be considered. The base component for analysis is a point topoint community of interest based on empirical network usage at agranular level reflecting every traffic type and routing condition.

[0095]FIG. 1 illustrates an exemplary telecommunications network, inassociation with the present invention, for implementing the callmonitoring service. The telecommunications network includes four endoffices, service switching point (SSP) 10, SSP 12, SSP 14 and SSP 16,which are class five switches in an embodiment of the invention. The endoffices may service any type of telephone system or network, including aCentrex system, a PBX system, an electronic key telephone system (EKTS)or a POTS system. In addition to the end offices, FIG. 1 depicts twointermediate routing switches, tandem switch 20 and tandem switch 22,which are class four switches in an embodiment of the invention. Thetandem switches 20 and 22 service the end offices, SSP 10, SSP 12 SSP 14and SSP 16. The exemplary network also includes a pair of signalingtransfer points (STPs), STP 30 and STP 32, and a service control point(SCP) 35.

[0096] Depending on the call origination, any of the end offices may beeither an originating or a terminating end office. For example, if acall is placed from a telephone serviced by the SSP 10 to a telephoneserviced by the SSP 14, the SSP 10 is the originating end office and theSSP 14 is the terminating end office. The SSPs 10, 12, 14 and 16include, for example, 1AESS or 5ESS switches manufactured by LucentTechnologies, Inc. (Lucent); DMS-100 and DMS-10 switches manufactured byNortel Networks Corporation (Nortel); AXE-10 switches manufactured byTelefonak-Tiebolaget LM Ericsson, or EWSD switches available fromSiemens Information and Communication Networks, Inc. The switches mayutilize an AIN Release 0.1 protocol. However, embodiments of the presentinvention may incorporate switches, such as ATM switches, that areincorporated into any alternative telecommunications technology. Thetandem switches 20 and 22 include, for example, the APX 800 MultiserviceAccess Switch manufactured by Lucent and the DMS-250 and the CVX 1800switches manufactured by Nortel.

[0097] By way of example, the SCP 35 is implemented with the BellcoreIntegrated Service Control Point, loaded with ISCP software Version 4.4(or higher), available from Telecordia, Murray Hill, N.J. In analternative embodiment of the invention, the SCP 35 may be a LucentAdvantage SCP, with software release 94, available from LucentTechnologies, Inc.

[0098] Implementation of the present invention may be upgraded toaccommodate future AIN releases and protocols and future trigger types.Specifications of AIN Release 0.1 SSPs may be found in BellcoreTR-NWT-001299, Switch-Service Control Point Application ProtocolInterface Generic Requirements, and Telecordia Technical ReferenceTR-NWT-001298, AIN Switching Systems Generic Requirements, thedisclosures of which are expressly incorporated by reference herein intheir entireties.

[0099] The solid lines among the end offices and the tandem switches inFIG. 1 are the existing trunks (or trunk groups) 62, 64, 66, 68, 70 and72, which indicate the existing routing design through the PSTN. Thetrunk group 72 is a direct trunk group between the SSP 14 and the SSP16, which represents a point-to-point community of interest. Therefore,a call originating from a telephone serviced by the SSP 14 to atelephone serviced by the SSP 16 is ideally routed directly from theoriginating end office, SSP 14, to the terminating end office, SSP 16,with no routing through intervening tandem switches. In other words, thecall involves a single or direct “hop” from the originating end officeto the terminating end office. The decision to implement a direct trunkgroup is based on engineering considerations, indicating a sufficientflow of traffic between the SSP 14 and the SSP 16 to warrant thededicated trunk group 72. As stated above, conventional engineeringconsiderations are based on sampled data from a single network elementand often fail to represent the true offered load, especially duringpeak activity.

[0100] The trunk groups within other point-to-point communities ofinterest are likewise the result of engineering design considerations.For example, telephone calls originating at the SSP 10 and terminatingat the SSP 16 follow the trunk group 62 to the tandem switch 20, thetrunk group 66 to the tandem switch 22 and the trunk group 70 to SSP 16.In other words, the call involves three “hops” to reach the terminatingend office. The routing is a result of design criteria indicating thatconnection requests between the SSP 10 and the SSP 16 were relativelyinfrequent, and therefore did not warrant a direct trunk connectionbetween the two, or even routing through a single, intervening tandemswitch.

[0101]FIG. 1 further depicts an exemplary data network of the invention,including a client 52, a network server 54 and an application server 42,connectable through a data network, such as an intranet 50, which is apacket switched data network. The client 52 includes a graphical userinterface (GUI) 51, e.g., a personal computer (PC), operating clientsoftware 53. The client 52 and the client software 53 may be implementedwith an IBM Pentium based PC, for example, using the Microsoft Windows98 or Microsoft Windows NT operating system, available from MicrosoftCorporation. The client software 53 further includes a web browser, suchas Microsoft Internet Explorer or Netscape Navigator, available fromNetscape Communications Corporation. In an embodiment of the invention,the client software 53 may further include any design software capableof processing the network data stored, for example, at the applicationdatabase 46.

[0102] The application server 42 may be a UNIX server, for example, andis capable of receiving information from the PSTN via the signaling datacollection application 44. The application server 42 is also connectedto the application database 46, which is an historical database forstoring design related data, such as PSTN network configurations,historical usage, offered load data, and the like. The applicationdatabase 46 enables engineering analysis of the traffic and routingopportunities in the PSTN. The application server 42 may also maintainauthentication data that limits access to at least the applicationdatabase 46 in order to protect proprietary information of the networkprovider. The authentication data may include, for example, a usernumber and an associated password or other personal identification.

[0103] To enable design based on the data in the application database46, the trunk planners and/or network design engineers access the systemthrough the network server 54. For example, an engineer connects fromthe client 52 to the network server 54 through the intranet 50. Thenetwork server 54 then connects to application server 42. In anembodiment of the invention, the application server 42 may be accessedby the client 52 via secure connections through the Internet, using forexample, secure sockets layer (SSL) protocol, developed by NetscapeCommunications. The network server 54 runs, for example, the Linux orMicrosoft Windows operating system and the Apache web server software,available from the Apache Software Foundation, or the Jigsaw web serversoftware, available from World Wide Web Consortium (W3C). The networkserver 54 receives, for example, HTTP messages from the client 52 andprovides HTML web pages in response to the subscriber's input. When theapplication server 42 is also used for authentication, it receivesauthentication data from the client 52 via the network server 54 andverifies the authentication data before enabling access to theapplication database 46. Alternatively, the client 54 may connect to theapplication server 42 via the intranet 50 without passing through anadditional network server.

[0104] The application server 42 retrieves network design data from theapplication database 46, including potential primary and intermediatehigh usage trunk groups, as well as traffic misroutes, discussed indetail below. The application server 42 may also retrieve previouslystored network design information regarding the current setup of thetelecommunications network, as well as traffic monitored at the endoffices. In an embodiment of the invention, the application server 42includes PSTN design application software that enables the networkdesign and includes, for example, calculators running the predeterminedtraffic engineering algorithms and actionable database reports listingthe identified primary and intermediate high usage direct trunk groupopportunities and misrouted traffic data. An interactive connection ismaintained among the application server 42, the application database 46,the network server 54 and the client 52, enabling the network designengineer to access, review and incorporate the trunk design data in thedesign process.

[0105] The signaling data collection application 44 shown in FIG. 1 maybe an SS7 based application, such as Sentinel, available from Tekelec,Inc., LinkQuest II, available from Tekno Industries, Inc., AcceSS7,available from Agilent Technologies, or Mass Data Collection (MDC),available from Telecordia. The signaling data collection application 44collects raw signaling data from the PSTN by monitoring the SS7 links(e.g., A-links, B-links and D-links) among the switches (e.g., the classfour and class five switches) and the associated STP. Alternatively, theSS7 data may be monitored and collected from interconnecting STP pairs.FIG. 1 depicts the SS7 signaling data being collected from links betweenthe tandem switches 20 and 22 and the associated pair of STPs 30 and 32,as indicated by the dashed line 45.

[0106] The individual SS7 messages that set up telephone calls throughthe PSTN are collected and correlated to produce a call detail record(CDR) related to each call. The SS7 messages include, for example, aninitial address message (IAM) that indicates the time the call wasplaced, the calling party number, the called party number and the switchaddresses. The SS7 messages also include answer data with respect to thecalled party, such as an answer complete message (ACM), which indicatesthat the call is received and the called party line is not busy, and ananswer message (ANM), which indicates that the call has been answeredand includes the time the called party goes off-hook in response to thecall. The SS7 messages that indicate the termination of a call included,for example, a release (REL) message, which indicates when one of theparties goes back on hook, ending the call, and a release complete (RLC)message, which indicates that the called party line is no longer in use.A CDR corresponding to a call is then derived, in part, using thestandard SS7 signaling messages. For example, the circuit duration maybe determined by comparing the IAM and REL messages, while theconversation duration may be determined by comparing the ANM and the RELmessages.

[0107] Referring to FIG. 1, the CDRs are sent from the SS7 datacollection application 44 to the application server 42 for processing.In an embodiment of the invention, each CDR includes the followingparameters: time and date of the call, circuit duration, conversationduration, release status, multi-hop counter, origination point code,destination point code, called number, calling number, charged number,redirect flag, local routing number (LRN), generic access profile (GAP)(for wireless calls), trunk circuit identification code (TCIC), carrieridentification code (CIC), traffic type (e.g., voice, 64 kbps) andSS7/multifrequency interworking. Significantly, for purposes of thepresent invention, the multi-hop counter indicates the number of calllegs used to complete the call, i.e., the number of switches to whichthe call is routed from the originating end office, including theterminating end office and the intervening tandem switches. For example,a call that proceeds from the originating end office directly to theterminating end office is a single hop call. Based on the CDRs receivedvia the SS7 data collection application 44, the application server 42identifies current routing from endpoint to endpoint, analyzes theextent of traffic handled by the switches based on the current routing,and identifies optional routing, if appropriate according topredetermined load parameters, discussed below.

[0108]FIG. 2 is a flowchart depicting the application logic of a typicalanalysis performed by the application server 42 to identifyopportunities for high usage direct trunk groups, according to anembodiment of the invention. In other words, the application server 42determines whether the volume of traffic between two terminal locations(e.g., switches) warrants establishing a direct trunk group between thetwo locations. High usage opportunities between end offices (e.g., classfive switches) are referred to as primary high usage direct trunk groupopportunities. High usage opportunities between tandem switches (e.g.,class four switches), or between tandem switches and end offices, arereferred to as intermediate high usage direct trunk group opportunities.FIG. 2 is discussed in the context of identifying primary high usagedirect trunk group opportunities, although the process is equallyapplicable to identifying the intermediate high usage direct trunk groupopportunities.

[0109] At step s208, a point-to-point community of interest is generatedbased on an algorithm developed through network engineering. Apoint-to-point community of interest isolates the traffic between thetwo endpoints, i.e., the A and Z locations. In order to facilitateexplanation, FIG. 2 illustrates generating (and processing) only onepoint-to-point community of interest. However, the invention encompassesperforming the steps of FIG. 2 with respect to multiple communities ofinterest, and associated data, simultaneously or consecutively. Eachpoint-to-point community of interest encompasses base components,defined by at least the following parameters resulting from theengineering algorithm: the identity of the A location, the identity ofthe Z location, the traffic type and pattern (e.g., one-way or two-way)between the two locations, an hour of the day, the minutes of use withinthe hour, the number of call attempts and completions, the average holdtime during the hour, and the identity of the required trunk groupswithin the point-to-point community of interest based on the existingtraffic engineering rules.

[0110] To identify primary high usage direct trunk group opportunities,the A and Z locations are the originating and terminating end offices.For example, FIG. 1 depicts six point-to-point communities of interestrelevant to the primary high usage direct trunk group analysis: SSP10-SSP 12, SSP 10-SSP 14, SSP 10-SSP 16, SSP 12-SSP 14, SSP 12-SSP 16and SSP 14-SSP 16. However, the A and Z locations may include ISPserving numbers, remote switches serving designated codes, and the like.Depending on the scope of the engineering analysis, when identifyingintermediate high usage direct trunk group opportunities, the A and Zlocations also include intermediate switching points, such as tandemswitches and other class four switches.

[0111] At step s210 of FIG. 2, data is collected corresponding to thepoint-to-point community of interest generated in at step s208 throughthe SS7 data collection application 44, as discussed above. In theembodiment of the invention shown in FIG. 2, the SS7 signaling data iscollected only at the tandem switches 20 and 22. In other words, no SS7signaling data is taken directly from the end offices, SSPs 10, 12, 14or 16. By monitoring only the tandem switches, less data is collectedand processed, thus increasing the efficiency of the design analysis.Furthermore, the tandem switches provide sufficient data to enablethorough design analysis because all of the traffic in thetelecommunications network passes through the tandem switches, exceptfor the traffic between end offices connected by direct trunk groups(e.g., direct trunk group 72 between the SSP 14 and the SSP 16).However, the direct trunk group traffic is not necessarily relevant tothe design analysis, unless the direct trunk group traffic between endoffices appears at a tandem switch, which would be apparent based on theSS7 signaling data taken from the tandem switch. For example, theappearance of the end office direct trunk group traffic at a tandemswitch may indicate an overflow condition or misrouting of the directtrunk group traffic, as discussed below. In alternative embodiments ofthe invention, the SS7 signaling data may likewise be collected from theend offices.

[0112] The application server 42 quantifies the peak busy hour offeredload for the point-to-point community of interest at step s214, based onthe data received from the PSTN via the signaling data collectionapplication 44. The peak busy hour offered load is measured based on thetraffic between the two end locations in discrete hourly time periods.The busy hour offered load determination may be based on the hourinvolving the heaviest traffic over a 24 hour time period, or it may bebased on data collected over several days and averaged. Designing to thehighest traffic period assures that the resulting network is able toaccommodate the call volume even when point-to-point communities ofinterests sharing network elements have simultaneous peak busy hours.The peak busy hour offered load is measured and stored in centum-callseconds (CCS) (i.e., 100 seconds of a telephone connection) to assure anaccurate quantification of the load on the affected switches.Alternatively, the offered load may be measured in call volume, althoughthe results may be skewed due to an excessive number of unusually short(or long) telephone calls.

[0113] At step s216, the peak busy hour offered load for the subjectpoint-to-point community of interest is compared to a high usagethreshold number X, predetermined by network engineering as the minimumoffered load justifying a dedicated direct trunk between the switches.The determination of X is subjective, and depends on consideration ofmany factors in addition to call volume, such as economic, contractualand network limitations. For example, economic limitations include therelative cost of adding an incremental circuit, such as the cost ofadditional switches or trunk groups, and corresponding budgetconstraints. Contractual limitations include consideration of agreementsto dedicate predetermined amounts of switch capability to alternatecarriers, such as CLECs and IXCs. The network limitations are defined bythe existing network infrastructure, and include considerations of theexisting resources and potential access to these resources for callrouting. Based on typical considerations, an example of X may be 24voice grade, 64 kbps circuits, which translates to approximately 540ccs.

[0114] When the offered load is less than the threshold X, dataindicating this fact is stored in the historical application database 46for future reference by network engineering at step s226. The processmay then repeat itself with respect to other point-to-point communitiesof interest, as described above.

[0115] When the offered load exceeds the threshold X, the applicationserver 42 determines whether a direct trunk group already exists betweenthe locations A and Z at step s218. In an embodiment of the invention,the determination is made using an interface to a Legacy operationsupport system, such as a trunk integrated records keeping system(TIRKS) or a total network data system (TNDS). For example, the directtrunk group 72 already exists between the SSP 14 and the SSP 16 ofFIG. 1. When a direct trunk group exists, the application server 42identifies the community of interest as an augmentation opportunity forother existing high usage direct trunk groups at step s220. Theaugmentation opportunity is stored in the application database 46 atstep s226 for future reference.

[0116] When it is determined at step s218 that there is no direct trunkgroup existing between the locations A and Z, the application server 42identifies the point-to-point community of interest as a new primaryhigh usage direct trunk group opportunity at step s222. In other words,based on the empirical signaling data collected from the tandem switchesin the PSTN by the application server 42, the call volume between thelocations A and Z is determined to be sufficient to warrant a directtrunk group connection between the two locations. At step s224, theapplication server 42 sizes the new direct trunk group opportunity byestimating the initial traffic load on the direct trunk group, based onthe SS7 signaling data, if it were implemented between the subject endoffices. Sizing the new primary high usage direct trunk groupopportunity includes application of traffic engineering algorithms, suchas the well-known Erlang-B traffic engineering algorithm. Application ofthe traffic flow algorithm associates the number of serving trunks withoffer load capacity and associated grade of service (GOS) and percentageof call blocking. The application server 42 may also perform theconversion of estimated traffic load to a specific number of trunks (ortrunk groups) sufficient to accommodate the estimated load.

[0117] At step S226, information regarding new primary high usage directtrunk group opportunities is stored in the application database 46,including the identity of new primary high usage direct trunk groupopportunities. The application database 46 may further includecorresponding estimated initial traffic load and number of trunks tohandle the estimated traffic load. The stored information issubsequently included in engineering considerations, using the peak busyhour offered loads and a recommended GOS (e.g., 1 percent chance ofreaching a busy signal) and objective probability of blocking (e.g., 99percent successful call completion). Use of the information againdepends on numerous considerations, including economic, contractual andnetwork limitations. For example, an engineer may determine to implementmore trunks than specifically calculated by the application server 42,based on anticipated increases in traffic or a desired higher thannormal quality of service in the particular community of interest. Theengineering effort is enabled in an embodiment of the invention byaccessing the application server 42 and the application database 46 fromclient 52 via the intranet 50, as discussed above.

[0118] When a new primary high usage trunk group opportunity isimplemented, a direct trunk group is added to connect the locations Aand Z of the point-to-point community of interest. By implementing adirect connection, the need for at least one trunk group to anintervening tandem switch (i.e., one hop) is eliminated. By building outa primary high usage trunk group opportunity, the current traffic andfuture traffic growth is relieved from the bypassed tandem switch,providing immediate and long term relief. As a result, a tandem switchexperiences a decrease in required digital signal ports (e.g., DS-0ports) and facilities from both the inbound and outbound legs. Thereduction in load is approximately two ports for every new (oraugmented) direct trunk group added to transit or bypass a single tandemswitch, and four ports for every new (or augmented) direct trunk groupadded to transit two tandem switches.

[0119]FIG. 3 is a block diagram depicting the exemplarytelecommunications network of FIG. 1 after high usage direct trunk groupopportunities have been identified. The dashed line 80 shows a newprimary high usage direct trunk group opportunity between the SSP 12 andthe SSP 14, which was identified according to the procedure of FIG. 2.Implementation of the new primary high usage direct trunk group 80relieves traffic directed through the tandem switch 20 and the tandemswitch 22. In other words, the routing of calls originating at the SSP12 and terminating at the SSP 14, would be reduced from three hops toone hop through the PSTN.

[0120] As stated above, the application logic of FIG. 2 may also beapplied to identify new intermediate high usage direct trunk groups,although the value of the threshold offered load X applied at step s216may differ for determining the intermediate high usage direct trunkgroup opportunities, depending on design considerations. At least one ofthe A and Z locations of the point-to-point communities of interest mustbe an intermediate or class four switch. For example, referring to FIG.1, a point-to-point community of interest exists between the SSP 10 andthe tandem switch 22. When the traffic between these locations exceedsX, the community of interest between the SSP 10 and the tandem switch 22will be identified as a new intermediate high usage direct trunk groupopportunity, indicated by the dashed line 81 in FIG. 3. Implementationof the new intermediate high usage direct trunk group opportunityrelieves traffic directed through the tandem switch 20.

[0121] Implementing intermediate high usage direct trunk groupopportunities may result in an end office being “rehomed” to anothertandem switch. For example, referring to FIG. 3, the existing “hometandem” for the SSP 10 is the tandem switch 20 and an existing “fartandem” for the SSP 10 is the tandem switch 22. When the direct trunkgroup 81 is implemented, the SSP 10 is “rehomed” from the tandem switch20 to the new home tandem, tandem switch 22. Implementation of thedirect trunk group 81 necessarily impacts the traffic among the tandemswitches in the PSTN, which must be analyzed.

[0122]FIG. 4 is a flowchart depicting the process for accuratelyestimating the sizing of the intermediate high usage direct trunk groupsto a new tandem switch using empirical demand data supplied through theSS7 data collection application 44. Accordingly, the end offices thathave been rehomed to a new tandem switch are identified at step s410. Inthe above example, the SSP 10 is identified as a rehomed end office. Atstep s412, all other end offices homed (and rehomed) to the new tandemswitch are also identified. For example, the SSP 14 and the SSP 16 wouldbe identified as end offices homed to the new tandem switch, tandemswitch 22. Likewise, all of the end offices that remain homed to thetandem switch to which the rehomed end office was originally homed, aswell as end offices homed to any tandem switches in the relevant portionof the telecommunications system other than the new tandem switch, areidentified at step s414 and may be designated as far end offices. In theexample, the only other end office depicted in FIG. 3 not homed to thetandem switch 22 is the SSP 12, which remains homed to the tandem switch20.

[0123] At step s416 the peak busy hour offered load is quantified fortraffic between each end office not homed to the new tandem switch(i.e., each far end office) and each end office homed to the new tandemswitch. For example, the peak busy hour offered load would be quantifiedfor traffic between the SSP 12 and the SSP 10, the SSP 14 and the SSP16, respectively. The peak busy hour offered load is compared to apredetermined threshold Y at step s418 for each pair of end offices.(The threshold Y may correspond to the intermediate high usage directtrunk group opportunity threshold, discussed above.) Like the thresholdX, described above, the threshold Y is set based on numerous engineeringconsiderations, including economic, contractual and network limitations.Based on such considerations, the threshold Y may also be set, forexample, to 24 circuits.

[0124] When the peak busy hour offered load does not exceed Y for a pairof end offices, the information is simply recorded in the applicationdatabase 46 at step s424 for future design and engineeringconsideration. However, a pair of end offices having a peak busy houroffered load greater than Y is identified as a new intermediate highusage trunk group opportunity at step s420. The new intermediate highusage direct trunk group opportunity is sized at step s422 to determine,for example, the estimated initial traffic load and the correspondingnumber of trunks needed to handle the traffic load. Sizing the newintermediate high usage direct trunk group opportunity includesapplication of traffic engineering algorithms, such as the well-knownNeal-Wilkinson traffic engineering algorithm. The new direct trunk groupopportunity and the associated sizing information is stored in theapplication database 46 at step s424. To facilitate explanation, FIG. 4depicts comparing and processing an offered load of only one pair oftandems, homed and not homed to the new tandem. However, multipleoffered loads for multiple pairs of tandems may be accommodated byrepeating steps s416 to s424.

[0125] In a related example, design engineering determines that a newtandem switch 24 is warranted to service the SSP 16, based on analysisof empirical traffic flow data, as discussed above. FIG. 5 shows anexemplary telecommunications network including the additional tandemswitch, new tandem switch 24, which is implemented with a direct trunkgroup 71 connection to the SSP 16. In other words, the SSP 16 has beenrehomed from the tandem switch 22 to the new tandem switch 24.Therefore, the SSP 16 is identified as having been rehomed to the newtandem switch 24 at step s410 of FIG. 4. At step s412, it is determinedthat no other end offices have been rehomed to the new tandem switch 24.At step s414, the SSP 10, the SSP 12 and the SSP 14 are identified asthe end offices not homed to the new tandem switch 24. The peak busyhour offered load is therefore quantified between the SSP 16 and each ofthe other end offices at step s416.

[0126] When an offered load exceeds Y, as determined at step s418, therelationship is identified as a new intermediate high usage trunk groupopportunity at step s420. The potential intermediate high usage trunkgroup opportunities are depicted in FIG. 5 by dashed lines 85, 86 and 87connecting the SSP 10, the SSP 12 and the SSP 14 to the new tandemswitch 24, respectively. The new intermediate high usage trunk groupopportunities are sized accordingly at step s422 and stored in theapplication database at step s424. When an offered load does not exceedY, the respective end office routes calls to the rehomed end office SSP16 in accordance with the existing trunk groups. For example, when thepeak busy hour offered load between the SSP 10 and the SSP 16 isdetermined to be less than Y at step s418, network engineering wouldlikely determine to route calls originating at the SSP 10 through thetandem switch 20, through the tandem switch 22, through the new tandemswitch 24, to the rehomed SSP 16.

[0127] In addition to relieving overburdened tandem switches, designengineering may increase network efficiency and further reduceassociated costs by identifying and correcting traffic misrouted in theexisting network. Traffic misroutes occur when an available andpreferred route is not selected by an originating end office during callsetup. A routing error of this type is usually caused by an error intelephone exchange code translation, such as the numbering plan area(NPA)/local exchange (NXX) code. Correcting traffic misroutes eliminatesat least one hop between the originating end office and the terminatingend office, increasing network efficiency, taking advantage of existingdirect trunk groups between end offices and reducing the traffic load onthe tandem switch to which calls were being misrouted.

[0128]FIG. 6 is a flowchart of exemplary application logic performed bythe application server 42 to identify traffic misroutes. Again, theapplication server 42 receives the empirical data for analysis from thePSTN via the SS7 data collection application 44. At step s610, apoint-to-point community of interest is identified having in-serviceprimary high usage direct trunk group between two end offices. Forexample, referring to FIG. 1, the community of interest incorporatingthe SSP 14 and the SSP 16 includes the primary high usage direct trunkgroup 72. At step s612, a base component is generated for apredetermined time period for the point-to-point community of interest.Although FIG. 6 depicts generating the base component for only one timeperiod of one point-to-point community of interest, the inventionencompasses generating (and processing) multiple time periods forcorresponding multiple point-to-point communities of interest. Forexample, the base component may be generated for each hour in a 24 hourperiod for a point-to-point community of interest.

[0129] At step s614, conduct time-synchronous verification of the directtrunk group overflow conditions for the same point-to-point community ofinterest over the same predetermined time period. For example, in anembodiment of the invention, the time-synchronous verification may alsobe conducted for each hour of a 24 hour period. The data for generatingthe base component and conducting the time-synchronous verification isalso collected via the SS7 data collection application. Because the SSP14 and the SSP 16 do not directly provide SS7 signaling data to the SS7data collection application 44 in the depicted embodiment, the existenceof an overflow condition is determined by examining data from a Legacyoperation support system, generally used for maintenance applications,such as TNDS or a data collection operations system (DCOS). Thetime-synchronous verification data may be collected contemporaneouslywith the base component data, or otherwise.

[0130] The application server 42 determines at step s615 whether atandem base component included in the point-to-point community ofinterest shows traffic during each hour over the 24 hour period. Forexample, it is determined at step s615 whether the SS7 signaling datafrom the tandem switch 22 indicates traffic between the SSP 14 and theSSP 16 for each hour in a 24 hour period. When there is no traffic inthe tandem switch 22, this information is simply stored in theapplication database 46 at step s622 for historical reference and thenext tandem base component is analyzed, i.e., the process returns tostep s614. When the base component of the tandem switch 22 indicatestraffic flow between the SSP 14 and the SSP 16, the application server42 compares at step s616 any overflow conditions experienced by thedirect trunk group 72, as determined at step s614. When an overflowcondition existed during the same predetermined time period, then thetraffic through the tandem switch 22 is apparently warranted and theinformation is simply stored in the application database 46 at steps622.

[0131] However, when no overflow condition existed in the direct trunkgroup 72 during the same predetermined time period, the traffic passingthrough the tandem switch 22 has been misrouted. In other words, a moredirect and preferable route was available (i.e., the direct trunk group72), yet the originating end office, the SSP 14, routed the trafficthrough the tandem switch 22 to the SSP 16. At step s618, theapplication server 42 flags the NPA/NXX code of the misrouted calls as amisrouted code. Also, the misrouted traffic is aggregated in order toaccurately quantify the impact on the tandem switch 22 at step s620. Thedata regarding the misrouted traffic is stored in the applicationdatabase 46 at step s622 for use in subsequent network designengineering considerations.

[0132] Although the invention has been described with reference toseveral exemplary embodiments, it is understood that the words that havebeen used are words of description and illustration, rather than wordsof limitation. Changes may be made within the purview of the appendedclaims, as presently stated and as amended, without departing from thescope and spirit of the invention in its aspects. Although the inventionhas been described with reference to particular means, materials andembodiments, the invention is not intended to be limited to theparticulars disclosed; rather, the invention extends to all functionallyequivalent structures, methods, and uses such as are within the scope ofthe appended claims.

[0133] In accordance with various embodiments of the present invention,the methods described herein are intended for operation as softwareprograms running on a computer processor. Dedicated hardwareimplementations including, but not limited to, application specificintegrated circuits, programmable logic arrays and other hardwaredevices can likewise be constructed to implement the methods describedherein. Furthermore, alternative software implementations including, butnot limited to, distributed processing or component/object distributedprocessing, parallel processing, or virtual machine processing can alsobe constructed to implement the methods described herein.

[0134] It should also be noted that the software implementations of thepresent invention as described herein are optionally stored on atangible storage medium, such as: a magnetic medium such as a disk ortape; a magneto-optical or optical medium such as a disk; or a solidstate medium such as a memory card or other package that houses one ormore read-only (non-volatile) memories, random access memories, or otherre-writable (volatile) memories. A digital file attachment to e-mail orother self-contained information archive or set of archives isconsidered a distribution medium equivalent to a tangible storagemedium. Accordingly, the invention is considered to include a tangiblestorage medium or distribution medium, as listed herein and includingart-recognized equivalents and successor media, in which the softwareimplementations herein are stored.

[0135] Although the present specification describes components andfunctions implemented in the embodiments with reference to particularstandards and protocols, the invention is not limited to such standardsand protocols. Each of the standards for Internet and other packetswitched network transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP)represent examples of the state of the art. Such standards areperiodically superseded by faster or more efficient equivalents havingessentially the same functions. Accordingly, replacement standards andprotocols having the same functions are considered equivalents.

What is claimed is:
 1. A method for identifying misrouting of traffic ina telecommunications network, the method comprising: identifying acommunity of interest based on call signaling data, the community ofinterest comprising at least one intermediate switching locationconnected to a first terminal switching location connected by a directtrunk to a second terminal switching location; determining whethertraffic in the community of interest passes through the at least oneintermediate switching location during a predetermined time period;determining whether the direct trunk experienced an overflow conditionduring the predetermined time period; when traffic in the community ofinterest is determined to have passed through the at least oneintermediate switching location during the predetermined time period,and the direct trunk is determined not to have experienced an overflowcondition during the predetermined time period, designating anidentifier associated with the traffic that passed through the at leastone intermediate switching location as misrouted traffic.
 2. The methodfor identifying misrouting of traffic according to claim 1, furthercomprising: flagging the identifier associated with the misroutedtraffic to redirect the misrouted traffic through the direct trunk. 3.The method for identifying misrouting of traffic according to claim 1,further comprising: identifying a volume of the misrouted traffic; andquantifying a load on the at least one intermediate switch attributed tothe misrouted traffic based on the volume.
 4. The method for identifyingmisrouting of traffic according to claim 1, in which the signaling datacomprises out-of-band signaling data collected from the at least oneintermediate switching location in the telecommunications network. 5.The method for identifying misrouting of traffic according to claim 4,in which the out-of-band signaling data comprises signaling system 7(SS7) messages.
 6. The method for identifying misrouting of trafficaccording to claim 1, in which the at least one intermediate switchinglocation comprises a class four switch.
 7. The method for identifyingmisrouting of traffic according to claim 1, in which the first andsecond terminal switching locations comprise class five switches.
 8. Themethod for identifying misrouting of traffic according to claim 1, inwhich the identifier associated with the misrouted traffic comprises anexchange code.
 9. The method for identifying misrouting of trafficaccording to claim 8, in which the exchange code comprises a numberingplan area (NPA)/local exchange (NXX) code.
 10. A method for identifyingmisrouting of traffic in a community of interest of a telecommunicationsnetwork, the community of interest comprising at least a tandem switchconnected to a first end office switch connected by a direct trunk to asecond end office switch, the method comprising: generating a basecomponent relating to the community of interest based on out-of-bandsignaling data, the base component comprising a plurality ofpredetermined time periods and a volume of traffic passing through thetandem switch in the community of interest during each of the pluralityof predetermined time periods; determining whether the base componentindicates traffic through the tandem switch in the community of interestduring at least one of the plurality of predetermined time periods; whenthe tandem switch shows traffic, determining whether the direct trunkexperienced an overflow condition during the corresponding at least oneof the plurality of predetermined time periods; and when the directtrunk did not experience the overflow condition during the correspondingat least one of the plurality of predetermined time periods, identifyingat least one unique code associated with the community of interest as amisrouted code.
 11. The method for identifying misrouting of calls in acommunity of interest according to claim 10, in which the out-of-bandsignaling data comprises signaling system 7 (SS7) messages.
 12. Themethod for identifying misrouting of calls in a community of interestaccording to claim 10, further comprising: identifying a volume of thetraffic associated with the misrouted code; and quantifying a load onthe tandem switch attributed to the misrouted traffic.
 13. The methodfor identifying misrouting of calls in a community of interest accordingto claim 10, in which the at least one unique code comprises a numberingplan area (NPA)/local exchange (NXX) code.
 14. A system for identifyingmisrouting of traffic in a telecommunications network, the systemcomprising: a data collection application device, configured to receiveout-of-band signaling data from a public switched telephone network; andan application server connected to the data collection applicationdevice, the application server identifying a community of interest inthe public switched telephone network based on the out-of-band signalingdata received by the data collection application device, the communityof interest comprising at least one intermediate switching locationconnected to a first terminal switching location and a second terminalswitching location, the first terminal switching location beingconnected by a direct trunk to the second terminal switching location;the application server determining whether traffic in the community ofinterest passes through the at least one intermediate switching locationduring a predetermined time period and whether the direct trunkexperienced an overflow condition during the predetermined time period;and when traffic in the community of interest is determined to havepassed through the at least one intermediate switching location and thedirect trunk is determined not to have experienced an overflow conditionduring the predetermined time period, the application server designatingan identifier associated with the traffic that passed through the atleast one intermediate switching location as misrouted traffic.
 15. Thesystem for identifying misrouting of traffic according to claim 14,further comprising: an application database, connected to theapplication server, that stores information relating to at least thecommunity of interest, the determination of whether the traffic passedthrough the at least one intermediate switching location during thepredetermined time period, the determination of whether the direct trunkgroup experienced an overflow condition during the predetermined timeperiod, and the identifier.
 16. The system for identifying misrouting oftraffic according to claim 15, further comprising: a data networkconnecting the application server and the application database to atleast one graphical user interface and enabling analysis of the storedinformation.
 17. The system for identifying misrouting of trafficaccording to claim 14, in which the identifier comprises a numberingplan area (NPA)/local exchange (NXX) code.
 18. The system foridentifying misrouting of traffic according to claim 14, in which theout-of-band signaling data comprises signaling system 7 (SS7).
 19. Asystem for identifying misrouting of traffic in a community of interestof a public switched telephone network (PSTN), the community of interestcomprising at least one tandem switch connected to a first end officeswitch connected by a direct trunk to a second end office switch, thesystem comprising: a signaling system 7 (SS7) data collection device,configured to receive out-of-band signaling data from the PSTN; and anapplication server connected to the data collection device, theapplication server identifying the community of interest and determiningwhether traffic in the community of interest passes through the at leastone tandem switch in the community of interest during a predeterminedtime period, based on the out-of-band signaling data provided by thedata collection device; when traffic in the community of interest isdetermined to have passed through the at least one tandem switch, theapplication server further determining whether the direct trunkexperienced an overflow condition during the predetermined time period;and when the direct trunk did not experience an overflow conditionduring the predetermined time period, the application server designatingat least one exchange code associated with the traffic that passedthrough the at least one tandem switch as a misrouted code; wherein theapplication server, together with an associated database, is configuredto provide information relating to at least the community of interest,the tandem switch and the misrouted code to at least one graphical userinterface.
 20. The system for identifying misrouting of traffic in acommunity of interest of a telecommunications network according to claim19, in which the application server identifies a volume of the traffichaving the misrouted code and quantifies a load on the at least onetandem switch attributed to the misrouted traffic based on the volume.21. A computer readable medium for storing a computer program thatidentifies misrouting of traffic in a community of interest of atelecommunications network, the community of interest comprising atleast a tandem switch connected to a first end office switch and asecond end office switch, the computer readable medium comprising: agenerating source code segment that generates a base component relatingto the community of interest based on out-of-band signaling data, thebase component comprising a plurality of predetermined time periods anda volume of traffic passing through the tandem switch in the communityof interest during each of the plurality of predetermined time periods;a determining source code segment that determines whether the basecomponent indicates traffic through the tandem switch in the communityof interest during at least one of the plurality of predetermined timeperiods and, when the tandem switch shows traffic, determines whetherthe direct trunk experienced an overflow condition during thecorresponding at least one of the plurality of predetermined timeperiods; and an identifying source code segment that identifies at leastone unique code associated with the community of interest as a misroutedcode when the direct trunk did not experience the overflow conditionduring the corresponding at least one of the plurality of predeterminedtime periods.
 22. The computer readable medium for storing a computerprogram that identifies misrouting of traffic in a community of interestaccording to claim 21, in which the out-of-band signaling data comprisessignaling system 7 (SS7) messages.